<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatibale" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="/js/vue.js"></script>
</head>
<body>
  <div id="app">
      {{msg}}
  </div>
<br>
  <script>
   let app = new Vue({
   el:"#app",
   data:{ 
     msg:'ok'
      },
   beforeCreate() {
    console.log('实例创建之前');
    console.log(this.$data.msg);
   },
   created() {
    console.log('实例创建之前');
    console.log(this.$data.msg);
   },
    })
  </script>
</body>
</html>